Deep-sea mining risks for sharks, rays, and chimaeras

Area of Science:

• Marine biology
• Conservation science
• Deep-sea ecology

Background:

• Deep-sea mining poses significant risks to marine biodiversity and ecosystem function.
• Chondrichthyans (sharks, rays, and chimaeras) are vital components of deep-sea ecosystems.
• Areas Beyond National Jurisdiction (ABNJ) host unique and vulnerable deep-sea fauna.

Purpose of the Study:

• To assess the potential impacts of deep-sea mining on sharks, rays, and chimaeras in ABNJ.
• To identify species vulnerable to mining-related disturbances, including benthic and plume impacts.
• To evaluate the overlap between species' distributions and anticipated deep-sea mining footprints.

Main Methods:

• Spatial overlap analysis between 30 chondrichthyan species and projected mining areas in ABNJ.
• Assessment of vertical depth range overlap with benthic and discharge plumes.
• Evaluation of species' life history traits (e.g., egg-laying, feeding guilds) for susceptibility.

Main Results:

• 30 chondrichthyan species were identified with spatial overlap with deep-sea mining footprints.
• 83% of species overlapped with the benthic mining footprint, and 100% with discharge plumes.
• 17 species had >50% depth overlap with benthic impacts; filter-feeders overlapped with discharge plumes.
• 60% of affected species are already threatened, with 64.3% predicted to become threatened.

Conclusions:

• Deep-sea mining activities are likely to exacerbate extinction risks for vulnerable chondrichthyan populations in ABNJ.
• Updated risk assessments and robust monitoring are crucial before and during mining operations.
• Spatial protections and careful management of discharge plumes are recommended to mitigate impacts on deep-sea fauna.